Excavator



April '25, 1933. F. o. SNOW, JR

EXCAVATOH Filed June 25, 1931 7 Sheets-Sheet l main oo0@m@ 000 April 25,1933.

F. o SNOW, JR

EXCAVATOR Filed June 25, 1951 7 Sheets-Sheet 2 IIIII'IIIIIIIIIIII I av12 21/ Foederz'cFn 0. 8 no 20, J2 6y 6% Mr Ap F. o. SNOW, JR

EXCAVATOR Filed June 25, 1951 7 Streets-Sheet 3 dlZZi 5 April 25, 1933.o SNOW, JR 1,905,191

EXCAVAT OR Filed June 25, 1931 7 Sheets-Sheet 5 Inbe 27/50? Eedez aiek0.832010, J72,

6% 5,15% i gg April 25, 1933. F. o. SNOW, JR

EXCAVATOR Filed June 25, 1931' 7 Sheets-Sheet 6 lumen/770: fi'edezazlok0. Snow, Jae,

22 24 awr- Patented Apr. 25, 1933 .Y STATES P ATEgNT' om n seamen 0.wow, an, "OF WINCHESTER, ivmssacnnsnms, AssIG onino' MEAD- MORRISONMANUFACTURING COMPANY, or 'EAS'I. Bos'roN, =1vr-AssacnUsms,.n;e0R-

PORATION OF MAINE Application filed June 25,

This invention relates to power excava- (tors, and is concerned with anovel latchtripping mechanism forthe door ofthe excavating scoop. Theinvention will best be 5 understood by reference to the following tionof the mechanism which moves the scoop in and out, and controls suchmovements of the scoop;

Fig. 5 is a sectional view on line 55;of Fig. '4;

Fig. 5A is a plan of a portion of the mechanism shown in Fig. 5;

Fig. 5B is an elevation of the parts shown in Fig. 5A, as viewed fromtheright-hand sidethereot Fig, 6 is a sectional view 011 line 6.6 ofFig. 5;

'Fig. :7 Fig. '5;

a 8' is a plan of a portion of the latchis a sectional view online 7-7of controlling mechanism;

Fig. 9 is a side elevation of a portion of the 'latch-controlllngmechanism;

- Fig. :10 is an elevation of the-parts shown in Fig. 9, as Viewedfromthe. left-hand side of:Fi 9;

Fig. 11 is a sectional View; on line :ll ll of Fig.8; and

Fig-12 is a ,sectionalview on line 1212 ,of-Fig. '9. I

Referring to the drawings, and to the embodiment of the invention whichis illustrated therein, there isshown a scoop which may take variousforms, the one herein shown by way of example being a dipper 20,

' rigidly affixed to a dipper stick 21, some- EXCAVATOR 1931. Serial No.546,783.

times called a dipper handle, which is mounted to;sl ide lengthwise in agnijde 22, its outward .movement being limited by stop 23 afiixed tothe,dipperstiek, its inward movement loya' stop 24 'afiigzed to-. thedipper stick. The guide 2 2.is ;pive,ted at 25ron a.boom.26, thelatterbeing pivoted vat27 on a swingbody 28, which is monnted the dipperstick,-:and then .forwardly abont a sheave wheel; 39, which is coaxialwithlf the 'Wardly partway about za sheave wheel .40,

and thence rearwardly andlupwardly abont the drum 36,4towhich,.as;previously stated, thefirst .endof theeable is secured.'Y'Thus, it is evident that when :the 36LisQrotated clockwise, as viewed.in lFig. .1, the

crowd cable 34 is wound-inand, the lresiiltant .pull on the sheaveWheeli39.nngesthefdipper 1 stick 21 outwardly to G130Wd the 20 .into'the material to be excavated. i l i ep ck, c b ase'i-s antenata on'theboom 26, and}leadsttherefromgfirst forwardly" to and part way aboutafsheave .Wheel 42 at the-outer endwof stick, thence inwardly sandgrearvvardlyyto; 9

and over a sheave wheell43 ceaxial With-the sheave i v 9, t n e dQWWaIlY ad rearwardly under; a sheave wheel coazi ial with the sheave wheel.40, andthence lypwardly and rearwardly ,to the .npper .side 9 of thedrum336, to which gas before stated the I first end of the pnll-backzcable is seeured.

Thus, 1 it is i evident that 5.36 is rotated contraelockwise, the pulack cable 35 is wound; in and the'pull wh ch vis;

pivot 25, thence .rearwardly .and downbetween the journal bearing 47 anda collar 52, suitably secured to the "adjacent. end. of the shaft 45. aV

The'drum-36 is loosely mounted on the v xshaft 45, but may be driven'bythe latter through an appropriate clutch, herein comprising two clutchmembers 53 and 54, one secured to the'shaft, as by a key 55, and theother in the present instance being conveniently formed on the drum :36.Herein,

-power;is applied tothe shaft through a gear '56, conveniently formed onthe clutch mem- 57 5f appropriate material.

ber '53. The latter'is provided with a facing Engagement anddisengagement; of. the clutch is effected by sliding the drumand theclutch 'member carried thereby axially 0n the shaft. The clutch'isnormally disengaged by a spring 58 one end of which bears against a hub59 presented by the clutchmem'ber 53, and the other end against 'ayokeor collar 60, which in. turn operates 1 through a ball-thrustbearing 61 against a "hubp 62 presented by the drum36. Move mm-.- of theyoke or collar under the influence of the spring is limited by suitablemeans, herein stops comprising nuts 63 threaded ontostubs 64.wh'ichextend loosely through the clutch'member 53, and are fix- .edly securedto'theyoke or collar 60, as by being screwed intog-the' latter,

of the clutch member 53 toward the adjacent bearing 46 is prevented byashoulder Movement 65, presented by the'shaft 45. a v l Engagement oftheclutch in opposition to {the spring 58 iseffected by 'suitable mechan"ism, such as that disclosed in Letters; Patent No. 1,247,564, issued toAlmon 'E. Norris November 29, 1917, said mechanism comprisfi ing-acollar66 mounted on the shaft .45 presenting an abutment 67. fora ball-thrustbearing 68, which is interposedbetween' said drum 36. "Between said huband said abutabutment and a' hub, 69 presented. bythe ments, there is abody later to be described, --by' which the thrust of the collar 66through the thrust bearing-68 is communicated to the drum '36 'to slidethe latter axially against the yielding opposition presented by'Fthespring 58, thereby to effect engage-.

- ment oif the clutch members 53 and 54.

yoke" 70, encircling the collar '66 and pivoted at171 thereto',-;carries 'a' pair ofadjusting screws 72, presenting abutments '73 forendwise engagement with pins 74 carried by screws 75 threaded into nuts76 fixedly secured in the frame member 49. Simultaneous rotation ofthese screws in the proper direction causes an endwise thrust to beexertedagainst the abutments 73 carried by the yoke 70, thereby movingsaid-yoke and the thrust collar 66 toward the drum 36. V The clutchengaging screws 7 5 are formed on rockshafts 77, which, as shown in Fig.4,

are suitably connected to each other for simultaneous operation bybell-crank levers 78 and-79 secured to said shafts, and having arms 80and 81 connected to each a link or links 82.

Still referringto Fig. 4, a hand lever 83, fulcrumed on a pivot 84, issuitably conother by nected to the bell-crank lever 78 as by a link 85,an arm 86, a rockshaft8 an arm"-' V 88 and a link 89. This hand leverisshown in its neutral position'in Fig. 4. Movement of the handle towardthe left in Fig. 4,-

that is to say, toward the operator who stands facing the lever fromthat side, oper ates through the described mechanism to engage theclutch. When the lever. is moved back to its neutral position, theclutch releasing spring causes disengagement of the i clutch.

Referring again to Fig. 5, the shaft 45' is rotated by power in thedirection of the arrow thereon,that is to say, clockwise asyviewed inFig. 4. Accordingly, when the described clutch is engaged, the drum 36is rotated clockwise by the power of the engine or motor. There isassociated with the drum an automatic brake now to be described, whichpermits free rotation of the drumby power clockwise, butnormallyprevents rotation contraclockwise. Referring now-to Fig. 7, thisbrake comprises a brake-drum 90' herein conveniently formed as anintegral part of the drum 36, which brake-drum-cooperates with a brakemember exemplified bya brake-band 91 provided with two relativelymovable terminals 92and 93. These terminals are differentially connectedto a hanger, herein a link 94, which is pivoted at 95 to a suitablefixedsupport, such as a bracket 96, mounted on the base of' the machine.The terminal 92 is connected by one or more, herein a pair of'links 97and a pivot 98 to the link 94. Theterminal 93.

is connected to the link in a manner which"'" 12o will appear.presently. a

A suitably arranged spring 99 urges the link 94 toward the right (Fig. 7),that is to say, clockwise about its pivot-95, 'butin a generallycountraclockwise direction con-' sidered with reference to thebrake-drum. Movementof the link in such direction is "limited by anappropriate stop 100, herein conveniently formed as an integral part of;

the bracket 96. The spring ShOWIl -IS' helically coiled about 'a rod 101which extends freely through an opening 102 provided "in curved surface103 on the "link 94, said surfaee permitting limited rocking movement ofthe link with relation to the rod. The

other end of the spring rests against an abutment,'herein a'washer 104and a nut 105, the

latter beingthreadedonto the rodf101.

The relative arrangement of the brake parts thus far described is suchthat when the-brake drum is rotated clockwise'asviewed in Fig. 7, thespring '99 .yields and allows the link 94 to'swing towardtheleft,'thedifferential action of the brake-band thereby permitting the'latter torelax. I WVhen, however, there is any tendency of the brake- .dru'm'torotate contra-clockwise, such "tendency is resistedby automaticapplication of the brake. The brake may be r'elea'sedat will,'l1owever,by moving the terminal 93 clockwise, considered with reference to thebrake-drum. This is conveniently accomplished'by connecting the terminal93 to the link 94 by a rocking lever 106, having two short arms 107,which are side byside, and embrace said terminal, The link 94: isbifurcated to embrace the "rocking lever 106, as well as links 97 (seethe upper righthand portion of Fig. 5).

WV-henthelever 106is rotated contra'clockwise about" its fulcrum (Fig 7)its arms 107 swing toward the left, and 'thebrake-band is 'relai'ed,thereby freeing the brake-drum 90 and 1 allowing it to rotatecontraclockwise. It'shouldhere be understood that'this release of thebrake is effected without disturbing thespring 99 and link 9\4','th'atis to say, it is accomplished irrespective of the action of theautomatic brake applying means. I

The brake re'leasing lever is manually controlled by mechanism new to bedescribed, reference still being had at'fir'stito '7. r The lever 106 isprovidedjwith a second arm 108, "which is connected by a link'f109 tol'an arm 110, the latter (see Fig. 5A) being connected by a'link'111'toan arm 112 secured to la roc'kshaft 118, to the other endof which thereis'secured an arm 114, which is connected by a pair of links 115'to anarm'116'secu'1edto a rockshaft'117. vReferring again to Fig. 7, thelink-109'is arranged generally parallel with a straight line containin'g'the centers of the pivots of the link 94:,and the lever "106, andvhence does not interfere With the releasing action f movement ofthero'ckshaft 117 isyieldin'gly resisted by a spring '118,which isconnected to the 'rockshaft by an arm "1190f a bellis mounted to slide.

13ml position; bell-crank lever 79 is turned clockwise by the useof thehand lever 88, it tends to crank lever "120 secured to the rockshaft,

said arm being connected by a pivot 121'to rod 122, which carries 'anabutment 123 against which oneiend of the spring rests, while theother:end of the spring is seated against an abutment 124, in which the rodThe abutment 124'is provided with a pivot 125, whieh turns in theadjacent frame member 49. "When,

therefore, the rockshaft 117 is rocked about its axis and the frame 119swings to and fro, the rod 122 slides forward and back ward in the guide124,'and the latter rocks on its pivotal-mounting.

Release of the brake'in opposition to the to be described, 'refe'rencebeing had to Fig. 4. The bell-cranklever 120 is provided with a secondarm 126, connected by a pivot 12? to a sleeve 128, the latter'beingmounted to slide lengthwise on arod 129, which is in-thena- 'ture'ofalink connecting said arm to anarm 130 011the bell-crank lever 7 9,which it will be remembered is'one ofthelevers for operating'theclutch-engaging screws.

Two centering springs 131 and 132 encircling the rod 129, and interposedbetween the sleeve 128 and abutments 133 and 134 *car'ried'bytherod,'tendto restore the hand lever and the connected parts to theirneu- WVhen the arm 130 of the place the spring 132 under compression,and in so doing effects release ofthe automatic brake, inasmuchas itacts through-the sleeve 1 128, "arm 126, rockshaft 117, arm 116 (see''Figu5iA), links115, arm 114, rockshaft 113,

a'rm112, link111,arm 110, link 109 (see Fig.

'7) and arm 108,-to swing thebrake-releasing arms 107'of the lever 106contraclockwise to release the automatic brake. "Since thereleasingmovement of the brake. is through the interposition of thespring 132 (See'FigQ '4) the'release and reapplicfation of the brake canbe contrelled to arnicety, and it canbe "applied and released'gradually'and sensitively. V r The described connections between thehand lever and the automatic brake are such that movement'of the ihandlever from the neutral position shownin Fig. 4 toward the right (forwardfrom the operator.) release the automatic brake. Inthis, connection, it

will'b'e rememberedthatmovement of the .jhand lever to the left(backward toward .a "the operator)'engagesthe clutch. Thus it isapparent that when'the operator moves I the hand lever backward (towardhim), power is applied to rotate the drum 36 clockwise,'a's viewedinFig. 4. When the,

hand leveris restored 'to its neutral position, the clutch isdisengaged, and reverse rotation of the drum ,is prevented by theautomatic application of the brake. When, however, the operator movesthe hand lever .forward (from him), the automaticbrake is released, andthe drum is free to rotate contraclockwise.

. i I will now describe the'mech'anism for urging the drum in thedirection opposite to that of the shaft, andat high speed, referencebeing had to Fig. 5.. In the example shown, this mechanism is in theform of a planetary gearxset, and comprises an internal gear 135,secured as by a spline 136,

to the shaft 45, a sun gear. 137 (externally -toothed) secured' as bypins 138 to the drum '36, and one or more, herein three planet pinions139, meshing with the gears 135 and 137, andmounted to rotate on studs140 secured to a planet pinion carrier 141,'which is loosely mounted onthe hubd69 of the drum 36. 1

The planet pinion carrier presents a brake-drum 14 2, cooperating with abrake member, herein *a band 143,'about the brakedrum. Referring now toFig. 6, this band has two terminals 144 and 145, one of which 7 isanchored by a pin 146 to a bracket 147, "While the other is connected bya pivotal pin .148 to an arm 149 secured as by a key 150 to a rockshaftv151, which is coaxial with and coupled to the rockshaft 117 by a 7coupling 152..

. When the rockshat't 151 is rotatedcontraclockwise as viewed in Fig. 6,the band is contracted about the drum, and theplanet pinion carrier. isheld against rotation, thus causingthe planet pinions to rotateabout affiXed axis, and to rotate the sun gear 137 and the drum 36contraclockwise athigh speed,

Y The seating of the brake-applying arm 149 on the rockshaft 151 is suchthat anextreme forward niovement of thehand lever 83 (toward theright inFig. 4) causes this high e speed reverse rotation of the drum 36.- Thus"when the lever is; moved fromfits neutral position forward (toward therightin Fig.

4), the automatic brake. is firstreleased, and

7 "*further movement of the hand ilever'in the gearing intooperation. r

1 It will be remembered that when the drum same direction brings thehigh speed reverse '36 is rotated clockwise, it is coupled directly tothe drivingshaft by the clutch. It follows that the crowding cable,which is urgthedippcr into the material, is being 'woundinat the speedofthe drivingshaft.

V It will also-be remembered that when the.

planetary gea rsetis in operation, thedrum is rotated contraclockwiseand at high speed. Ittherefore follows that the pull-back, Cable ,iswound ina't acorrespondingly high speed,

; and that backward or idle. movement of the shovel consequently isspeeded up. The con- .trol" of. the forward 7 and backward move-f door.

place inflthe opening 157.

.ments of the dipper stick is vested in the.

hand lever 83, which therefore controls'the in and out movements of thedipper. It is important to remember this, because, aswill presentlyappearjthis same hand, lever car-.

'ries the device which controls the; tripping ofthedoor latch of thedipper, and hence the operatorcan trip the door latch at any instantlbythe same hand which controls the in and out movements of the dipper, and

"without relinquishing his grasp upon the" hand lever. I

The dipper, with its door and latch, and the latch-tripping mechanismwill now be described, reference being bad at'first to,s0

Figs. 2' and 3. As isusual, one end of the dipper,that"-is to say, thedigging end, is open, and the other endv is provided'with a door 153,which is pivoted at 154 at thetop of the dipper. This door is normallylocked 8 V in its closed position by a suitable latch I 155, which, asshown,is slidably mounted in a guide 156, the latter beinglsecured tothe V The lower end of the latch is normally received in an opening157in a plate.v 158 secured to the under side of the dipper. The latch isnormally held in door-locking position, andis restored to such positionby a suitably arranged'spring 159, one end of 'which abuts againstthefupper end of the latch, and the other against an abutment 160secured to. the door. A rod 161, secured to the upper end of thelatch,.extends through the spring, andthrough the abutment 160,

The latch may be li ftedinopposition to the spring by a latch-liftinglever 164, pivoted at 165 on the guide 156, and presenting,

abutments 166 engagingthe under side of anoverhanging abutment 167,presented by the, latch. Downwardswinging movement of the lever (andconsequently downward sliding movement of thez latch) is limited. 1

by an adjustable stop screw 168 threaded V .into'the'lever', andengaging at is lower end an abutment 169 on the outer face of'the (1001*153. a r p I The latch lever is lifted or tripped by av latch-trippingrope 17 0, suitably attached" to the lever, as by ajclevis 171, securedby a pm .172 to {a lug 173 presented by the lever.

This rope leads upwardly, and, as shown in Fig. 1, over a sheave wheel174 carried. 12 by the outer end of th'e; dipper stick,'-thencerearwardly between two sheave wheels 175 carried by the boom, thence.over two sheave wheels 176 and 177 at the'upper portion of the swingbody, thence f dowllwardly'over a vertically movable. sheavewheel 17.8,and

finally upwardly to the point 17-9, where it is dead-ended. Referringnow to. Fig. 4, it will be seen that the Vertically movable movabletraveler; 180,. whose. weight, to: gether with that of the sheave wheel.and

other associated. partscarried by the travel-i er, normallymaintains-the rope or cable in a condition in which it will not tripthelatch,...that is to say, as. the dipper stick moves inwardly, theweight of these parts takes up. the slack, as the. loop is. enlarged bythe descent ofv the take-up device, and on the other hand, when thedipper, stick ismoved outwardly, the take-up device rises.

By holding the take-up device fixed at any point in its verticalmovement, outward movement of the dipper stick may be utilized to causethe latch-tripping rope to exert a pull on the latch, and to trip thelatter To. this end, the traveler 180. carries anappropriate clamp (seeFig. 12),.comprising two clamping members18l and 182, disposed. onopposite sides, respectively, of a fixed vertical rod 183, Whose lowerend (.seeFig. 1) is. secured to. a: bracket 18a, and. whose. up.-. perend is bent horizontally asv at 185,.andv is secured to a. bracket 186..Referring again to Fig. 12, the olampingmembers 181 and, 182 are.connected to. each other at one pair of. ends by a pair of links 187,,and their other ends by an. arm 188, the latter being mounted on avertically disposed rockshaft 189, by means. which, in effect, is asplined connection, two sides. of the shaft being. slabbed ofi'as at190,and the arm 188 being correspondingly shaped to, fit the cross-sectionalshape of the shaft. The clamp is normally relaxedby a spring 191, one.end of which bears against a, lug 192: presented by the; clamping member182, while the other end rests against an abutment, herein. one ofa.pair'of nuts193, threaded onto, a rod 19.4, which extendsloosely throughsaid lug, and; is pivoted at 195 tolthe links 1 87 'The opening:movement of the clamp, under the influence of this spring, is.adjnstably limit-- ed by one of a pair of nuts 196, threaded onto therod 194, and engaging the-Lug 192.

Clamping action of the clamp in opposition to the spring is cause-dbyrocking the shaft 189 about its vertical axis thereby swinging the arm188 cont-raclockwise, thus to. cause the clamp 181* tov approach the rod183. The clamp- 182 is provided with a pair of ears 197', disposed,above and below the arm,1 88'an.dk about the rockshaft 189. The clampingmember 182' is attached to the traveler as by ears. 198. When,therefore, the: traveler moves up and down,

the clamp moveswith it. The rockshaft 189 is mounted in appropriateupper andlower bearings 199 and 200 .(seeFig; 4).

As already intimated, the control, of thev I latch preferably is vested.inthe. same hand which controls. the hand lever. 83 for conr,

trolling the in and. out movementslof the. dipper stick, To. thisend,.thereis 111011111},

ed on. the'lever 83 a latch controlling mem;

ber, herein a small lever 201 mounted, on. a

pivot 2O2'onv the lever 83, adjacent to, the. grasping portion of thelatte'r 'and; suitably connected to the described vertically" movabletraveler as by a link 203, WhQSQllP-g perend. is pivoted at 204.to.thelever 201, and whosev lower end. is pivoted at 205 to,

one arm 2060f a bell-crank lever 207', whose.-

other arm 208 is connected bya link; 209.110,

an arm. 210,:the latter being secured to the lower: end of. the.vertical rockshaft ),,be} low the base or floor plate 50,. Thepivotalf'connection 205. between thev link. 203 and.

the arm 206 is disposed with itsaxis sub-.

stantially coincident with the axis of the,

pivot 84, on which the lever .83 is: fulcrumed, as a result of whichrocking movementfo-f the lever 83 hasno effect upongthe'verticalg lymovable traveler.

squeezing the small lever 201' toward; the large lever 83, cause thetraveler to beheldin fixed position, as a consequenceof which,

outward movement of. thedi pper stick undet. the control of the lever.831wi ll. cause, the.

latch to he tripped. In practice, the 0 a erator by. forward .movement.of. the. level; 88 causes the dipper to bemovedloutwardly toward the pinwhere the load, is tonbe discharged, and just a few inchesbefore.

the dipper reaches that point, the operator,

presses his thumb or the palm, of the hand adjacent the base of the.thumb against the lever 201, thus squeezing. theqlatter to; Ward thegrasping portion, ofthe lever. 83.

A slight further movement ofthe. dipper in an outward direction causesthe door 1. In an excavator, the combination ofaf scoop provided. with a10 7, ilatGhUfQn;

holding said door closed,,. a, latch tripping rope, a. take-up for saidrope; aggnide for said take-up, a clampcarrred, by said take up, meansfor moving .said scoop, means, consequent upon movement ofSHJCLSGOOPJQO- cause said rope to tripsaid latch, and-means.-control-led' by the operator 7 tocause said clamp. to clamp said guide,therebytohold said take-up fixed, thereby .to predeterminethe, point inthe movement of said scoop,

when said rope will trip said latch.

On the other hand, however, at any point ii -the movement. of] the lever83, the operator may, by simply:

2. In an excavator, the'combination of a scoop provided with a door, alatch for holding said door closed, a latch-tripping rope,

:Ineans for moving said scoop, a normally operative take-up device whichmaintains saidropein a' condition in which it will not trip said latch,a guide for said take-up device, a clamp carried by said take-up device,and means at will to cause said clamp to clamp said guide, thereby torender said take-up device inoperative, thereby to cause 7 saidrope totrip said latch when said'scoop ismo ved. I r

3,111 an excavator, the combination of a scoop provided with a door, alatch for holding said door closed, a latch-tripping rope, means for'movingsaid scoop, a take-up detake-up'd'evice inoperative, thereby tocause said latch to betripped when movement of said scoop subjects saidrope to tension.

- 4.- In 'an excavator, the combination of a scoop provided with a door,a latch for holdingfsaid door closed, a latch-tripping rope connected tosaid latch,;a portion of said rope being arranged in the form ofa loop,

means to move said scoop to and fro, takeup means in said loopautomatically respon- V .sive to movements of said scoop to take upslack in said rope by varying the size of said loop, a guide for saidtake-up means, a clamp carried by said take-up means, and.

means at will to hold said take-up means fixed by causing said clamp togrip said guide;

5.'In an excavator, the combination ofa' scoop provided with a door, alatch for holdmg said doorrclosed, a latch-tripping rope connected tosaid latch, a portion of said rope being arranged in the form of a loop,means to move said scoop to and fro, gravi-r ty controlled take-up meansin said loop automatically responsive to movements of said scoop to takeup slack in said rope by varying the size of said loop, a vertical guidefor said take-up means, a clamp carried by said take-up means, and meansat will to' hold said take-up means fixed by causing said clamp to gripsaid guide.

6. In an excavator, the combination of a scoop provided with a door, alatch for holding. said door closed, a latch-tripping rope connected tosaid'latch,-a portion of said ,rope being arranged in the form of adepending loop, means to move said scoop to 7 and fro,gravity-controlled means including abody supported by said loop andvarying thesize of the latter as said scoop is moved to and fro, a guidefor said body, a clamp carr ed by said body, and means at will to holdsaid body fixed by causing said clamp to grip said guide."

7. In an excavator, the combination of a scoop provided witha door, alatch for hold,- ing said doorclosed, a latch-tripping rope, a take-upfor said rope, a guide for said take-up, a clamp carr ed by saidtake-up,

said clamp comprislng two clamping mem bers disposed on opposite s des,respectively, of said guide, means for moving said scoop,.meansconsequent upon movement of said scoop to vcause said rope to trip saidlatch, and meansco'ntrolled by the operator to move said clampingmembers toward each other and toward the interposed guide,; thereby tohold said take-up fixed, thereby to predetermine the point inthemovement o'fs'aid scoop whensaid' ropewill tripsaid latchu 8. Inanexcavator, the combination of a scoop provided with a door,.a latch forhold ing said. door closed, a latch-tripping rope,

atake-up for said rope, a guide for said take: up, a clamp carried bysaid take-up, said clamp comprising two clamping members disposed onopposite sides, respectively, of

said guide, a spring normally relaxing said a clamp, means for movingsaid scoop, means consequent upon movement of said scoop'to cause saidrope to tripsaid latch, and means controlled by tlie'opera'tor to movesaid clamping members toward each other and toward the interposed guide,thereby to hold said take-up fixed, thereby to pre'determine the pointin the movement of said scoop when said rope will tripv said" latch.

9. In an excavator, the combination 6f a scoop. provided with a door, alatch for holding said door closed,,a latch-tripping rope, a take-up forsaid rope, a guide for said take-up, a clampcarried by said take up,said clamp comprising two clamping members disposed on opposite sides,respec-, tively, of said guide, a spring normally re-' laxing saidclamp, means adjustably limit ing the relaxing movement of said clampunder the mfiuence of sa d sprlng, means for moving said scoop, meansconsequent uponmovement of said scoop to cause said rope to trip saidlatch, and meanscontrolled by the operator to move said clamping memberstoward each other-and toward thein: terposed guide, thereby to hold saidtake-up fixed, thereby'to predetermine the point'in the movement of saidscoop when said rope-,

will tripthelatch. V I 7 V 10. In an excavator, the combination of ascoop provided with a door, a latch for bold. ing said door closed, alatch-tripping rope,

a take-up 'for said rope, a guide for said take-up, a clamp carried bysaid take-up,

said clamp comprising two clampingmenr,

bers disposed on opposite sides, respectively,

of said guide, an armcarried by said takeup and connecting said clamplngmembers to each other, means for moving said scoop, means consequentupon movement of said scoop to cause said rope to trip said latch, andmeans controlled by the operator to move said clamping members towardeach other and toward the interposed guide, thereby to hold said take-upfixed, thereby to predetermine the point in the movement of said scoopwhen said rope will trip said latch.

11. In an excavator, the combination of a scoop provided with a door, alatch for holding said door closed, a latch-tripping rope, a take-up forsaid rope, a guide for said take-up, a clamp carried by said take-up,said clamp comprising two clamping mem bers disposed on opposite sides,respectively, of said guide, an arm carried by said take-up andconnecting said clamping members to each other, a rock-shaft extendinglengthwise of said guide and having a splined connection with said arm,means for moving said scoop, means consequent upon movement of saidscoop to cause said rope to trip said latch, and means controlled by theoperator to move said clamping members toward each other and toward theinterposed guide, thereby to hold said take-up fixed, thereby topredetermine the point in the movement of said scoop when said rope willtrip said latch.

12. In an excavator, the combination of a scoop provided with a door, alatch for holding said door closed, a latch-tripping rope, a take-up forsaid rope, a guide for said take-up, a clamp carried by said take-up,said clamp comprising two clamping members disposed on opposite sides,respectively, of said guide, a rock-shaft extending lengthwise of saidguide, a rocker-arm carried by said take-up and slidable lengthwise ofand on said rock-shaft, said rocker-arm having non-rotatable connectionwith said rockshaft and connected to said clamping members to urge themtoward said guide, means for moving said. scoop, means consequent uponmovement of said scoop to cause said rope to trip said latch, and meanscontrolled by the operator to move said clamping members toward eachother and toward the interposed guide, thereby to hold said take-upfixed, thereby to predetermine the point in the movement of said scoopwhen said rope will trip said latch.

13. In an excavator, the combination of a scoop provided with a door, alatch for holding said door closed, a latch-tripping rope, a take-up forsaid rope, a guide for said take-up, a clamp carried by said take-up,said clamp comprising two clamping members disposed on opposite sides,respectively, of said guide, a link connecting said clamping memberstogether at one pair of ends, an arm connecting said clamping memberstogether at their other pair of ends, means to rock said arm toficause.said clamping members, to; move one toward the other, means tor movingsaid: scoop, means consequent upon movement of; said scoop to cause saidnope totripsaiddatch, and means controlled by the operator to move saidclamping members toward each otherand; toward: the in: terposect guide,thereby to hold said; take-up fixed-,thereby, to; predetermine the-pointin the movement of said; scoopv when said-rope willttripisaid l'atch. ai

14%. In an: excavator, the: combination ofa scoop provided, with a door,a latch for hold ing said door closed, a-latch-trippingrope, a; takeupgfor saidrope, a guide for said take-up, a clamp carried by saidtake-up, saijdclamp comprising two clamping-members disposed on oppositesides, respectively, of said(gui de, aIlink; connecting said clampingmemberstogether'at one pair of ends, an arm connect-ing. said clampingmembers to-' gether at their other pair of ends, means to rocksaid armto cause said clamping members to, move one toward the other, a; springnormally tending to movesaid clamping, members apart, means for moving,said scoop, means consequent upon movement of said scoop; to cause saidrope. to trip said latch, and means controlled by the opera,- tor tomove said.v clamping members toward each other and: toward theinterposed guide, thereby to holdsaid take-up fixed, thereby topredetermine the point in the movement of said scoop when said ropewill, trip said; latch, v H

LE5, In an excavator, the combination ot a scoop provided with a door, alatch for holding said door closed, a latch-tripping rope, a takev-upfor said rope, aguide for saidtake-up, a clamp carried by saidtakeup,,saidclamp comprising twoaclamping members disposed on oppositesides, respect-ively, of said guide, a link connecting said clampingmembers together at one pairof ends, an arm connectingjsaid"clampingmembers together at their other pair of ends, means to roclgsaid arm tocause said clamping members to move one toward the other, a springconnected to said link and normally tending to move said clampingmembers apart, means for moving said scoop, means consequent uponmovement of said scoop to cause said rope to trip said latch, and meanscontrolled by the operator to move said clamping members toward eachother and toward the interposed guide, thereby to hold said take-upfixed, thereby to predetermine the point in the movement vof said scoopwhen said rope will trip said latch.

16. In-an excavator, the combination of a scoop provided with a door, alatch for holding said door closed, a latch-tripping rope, a take-up forsaid rope, a guide for said take-up, a clamp carried by said take-up,said clamp comprising two clamping members disposed onopposite sides,respectively, of said guide, a rock-shaft extending lengthwise of saidguide and extending through a one of said clamping members, a rocker-armthrough which said rock-shaft extends, said rocker-arms connecting saidclamping members together at one pair of ends, means connecting saidclamping members together at their other pair of ends, means for movingu said scoop, means consequent upon movement of sald scoop to cause saidrope to trip saidlatch, and means controlled by the operator to movesaid clamping members toward each other and toward the interposed guide,thereby to hold said take-up fixed, thereby to predetermine the point inthe movement of said scoop when said rope will-trip said latch.

, 17 In an excavator,the combination of a scoop provided with adoor, alatch for hold ing saiddoor closed, a latch-tripping rope, a take-up forsaid rope, a guide for said 'take-up,-a clamp carried by said take-up,

said clamp comprising two clamping members disposed on'opposite sides,respective.-

ly, ofs'aid guide, a'rock-sha-ft extending lengthwise of said 1 guideand extending through one of said clamping members, a rocker-arm throughwhich said rock-shaft extends, said rocker-arm connecting said clampingmembers together at one pair of' ends, a link connecting said clampingmem bers together at the other pair of ends, means for moving saidscoop, means'consequent upon movement ofsaid scoop to causesaid,

rope to trip saidlatch, and means controlled by the operator to movesaid clamping mem bers'toward each other and toward the interposedguide, thereby to hold said take-up fixed, thereby to predetermine thepoint in the movement of said scoop when said rope will .trip saidlatch.

In testimony whereof, I have signed my name to this specificationrFREDERICK o. sNow, JR.

